The researchers claim that other explanations for the circular feature, such as it being a cloud, or the accumulation of particles similar to a sand dune, are unlikely.

But Louise Prokter of Johns Hopkins University in Maryland, US, said the images were not of sufficient resolution to provide details below a few hundred metres, and suggested the dome might be an impact crater.

She suggested that, if the feature was indeed an icy volcanic dome, it could be formed by nitrogen ice breaking through the surface.

The Visual and Infrared Mapping Spectrometer (Vims) can discern wavelengths of light in the visible and infrared range of the spectrum in order to penetrate the thick organic haze which obscures Titan's surface.